Make the Scorpion King run into a pillar and hit his tail. Repeat this 3 more times and pick up the health sitting around. Then stand still until he gets mad. Hit his tail and his torso. Repeat this 2-3 more times. This time he will try to grab you. Run left and right at the right time and hit his tail. Then hit his torso. Then Jonathan or Meela will throw the spear but eventually will miss. Get the spear and throw it at him and you will win. Congratulations!